Professional Hidden Embedded Surveillance Cam?

We had great response to our covert camera test including a question today about hidden options to record for a few days. There are many consumer hidden surveillance cameras online, embedded into alarm clocks, motion detectors, teddy bears, etc.

Does anyone know of any high quality, professional level hidden / embedded cameras? What's attractive is the simplicity - just drop it down and let it go. However, the consumer offerings seem to get terrible reviews even from consumers.

Short of building one's own covert system, with pinhole lenses, cables to a dedicated DVR, etc., is there any turnkey hidden / embedded option that is designed for professional use? i.e., Police, corporate, or government investigations?

On the professional level, I would imagine there would be differences in image quality, low light performance, battery power, durability perhaps?

I have always wondered about the legality/liability of a camera in a non functioning smoke detector. Other cameras I have used were motions, clocks on the wall, and an a/c adapter. I have seen sprinkler heads, and exit signs.

The liability would be that people would expect the pseudo smoke detector to work or? Presumably, if you had enough real smoke detectors, this would eliminate the liability or?

False sense of fire security?

One "smoke camera" we installed was just hilarious because it was installed about a foot away from the existing functioning smoke. It was an inside job that we caught on camera.

Another planned install was scrubbed because of liability issues having no fire detection system in the business. We added a “motion” to the alarm system. We caught them too. They do have their place if planned out and installed properly.

I have a family member who needs a covert camera with low light ability, ability to record motion events for at least 24 hours if battery powered, but live feed isn't needed. Just need an offline camera that has decent resolution (720p or better) with either good low light abilities or IR. Would be nice if it was a simple SD card setup that she could just play in Windows Media Player. This can be powered by AC outlet, but should fit in with an office environment.